title: Selective adsorption and separation of chromium (VI) on the magnetic iron-nickel oxide from waste nickel liquid.
abstract: The selective adsorption of Cr (VI) from the wastewater of Cr (VI)-Ni (II) by magnetically iron-nickel oxide was investigated in this study. Synthetic iron-nickel oxide magnetic particles in the co-sedimentation method were used as adsorbent to remove hexavalent chromium ions. The characteristic of adsorption was evaluated by Langmuir, Freundlich isotherm and Dubinin-Kaganer-Radushkevich (DKR) equations in the simulation wastewater of Cr (VI)-Ni (II) bi-system. The energy spectra and FT-IR analysis were used to test adsorbent before and after adsorption. The obtained results suggest that the uptake of chromium (VI) effect is obvious from phosphate anions and that from others is unobvious. The maximum adsorption capacity of hexavalent chromium is about 30 mg/g at pH 5.00+/-0.02, and it was reduced by increasing the total dissolved substance (TDS) of system. Adsorption energies E are about 10.310-21.321 kJ/mol which were obtained from DKR equation in difference TDS conditions. The regeneration shows that the iron-nickel oxide has good reuse performance and the hexavalent chromium was recycled. The major adsorption mechanism proposed was the ions exchange; however the surface coordination was a main role in the condition of TDS less than 200mg/L.
authors.affiliation: Department of Chemistry, College of Chemical Engineering, Dalian University of Technology, Dalian, PR China.
authors.forename: Linsen
authors.initials: L
authors.lastname: Wei
authors.forename: Gang
authors.initials: G
authors.lastname: Yang
authors.forename: Ren
authors.initials: R
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000302:isolation & purification*; D003247:Conservation of Natural Resources / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D009532:Nickel / Q000737:chemistry*; D014867:Water; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; C000499:ferric oxide; D009532:Nickel; C028007:nickel monoxide